UNDERSTANDING THE EFFECTS OF GOVERNMENT SPENDING ON CONSUMPTION
Jordi Galí Javier Vallés CREI and Universitat Pompeu Fabra Economic Bureau of Spanish Prime Minister J. David López-Salido Federal Reserve Board
Abstract Recent evidence suggests that consumption rises in response to an increase in government spending. That finding cannot be easily reconciled with existing optimizing business cycle models. Weextend the standard new Keynesian model to allow for the presence of rule-of-thumb consumers. We show how the interaction of the latter with sticky prices and deficit financing can account for the existing evidence on the effects of government spending. (JEL: E32, E62)
1. Introduction
What are the effects of changes in government purchases on aggregate economic activity? How are those effects transmitted? Even though such questions are central to macroeconomics and its ability to inform economic policy, there is no widespread agreement on their answer. In particular, though most macroeconomic models predict that a rise in government purchases will have an expansion- ary effect on output, those models often differ regarding the implied effects on consumption. Because the latter variable is the largest component of aggregate
Acknowledgments: We wish to thank Alberto Alesina, Javier Andrés, Florin Bilbiie, Günter Coenen, Gabriel Fagan, Eric Leeper, Ilian Mihov, Valery Ramey, Michael Reiter, Jaume Ventura, Lutz Weinke, co-editor Roberto Perotti, two anonymous referees, and seminar participants at the Bank of Spain, Bank of England, CREI-UPF, IGIER-Bocconi, INSEAD, York, Salamanca, NBER Summer Institute 2002, the 1st Workshop on Dynamic Macroeconomics at Hydra, the EEA Meetings in Stockholm, and the 2nd International Research Forum on Monetary Policy for useful comments and suggestions. Galí acknowledges the financial support and hospitality of the Banco de España, and CREA-Barcelona Economics and MCyT (grant SEJ 2005-01124) for research support. Anton Nakov provided excellent research assistance. This paper was written while the last two authors worked at the Research Department of the Banco de España. The opinions and analyses are the responsibility of the authors and, therefore, do not necessarily coincide with those of the Banco de España, the Eurosystem, the Board of Governors of the Federal Reserve System, or any other person associated with the Federal Reserve System. E-mail addresses: Galí: [email protected]; López-Salido: [email protected]; and Vallés: [email protected]
Journal of the European Economic Association March 2007 5(1):227–270 © 2007 by the European Economic Association
“zwu001070405” — 2007/1/24 — page 227 — #1 228 Journal of the European Economic Association demand, its response is a key determinant of the size of the government spending multiplier. The standard RBC and the textbook IS-LM models provide a stark example of such differential qualitative predictions. The standard RBC model generally predicts a decline in consumption in response to a rise in government purchases of goods and services (henceforth, government spending, for short). In contrast, the IS-LM model predicts that consumption should rise, hence amplifying the effects of the expansion in government spending on output. Of course, the rea- son for the differential impact across those two models lies in how consumers are assumed to behave in each case. The RBC model features infinitely-lived Ricardian households, whose consumption decisions at any point in time are based on an intertemporal budget constraint. Ceteris paribus, an increase in gov- ernment spending lowers the present value of after-tax income, thus generating a negative wealth effect that induces a cut in consumption.1 By way of contrast, in the IS-LM model consumers behave in a non-Ricardian fashion, with their consumption being a function of their current disposable income and not of their lifetime resources. Accordingly, the implied effect of an increase in government spending will depend critically on how the latter is financed, with the multiplier increasing with the extent of deficit financing.2 What does the existing empirical evidence have to say regarding the con- sumption effects of changes in government spending? Can it help discriminate between the two paradigms, on the grounds of the observed response of consump- tion? A number of recent empirical papers shed some light on those questions. They all apply multivariate time series methods in order to estimate the responses of consumption and a number of other variables to an exogenous increase in government spending. They differ, however, on the assumptions made in order to identify the exogenous component of that variable. In Section 2 we describe in some detail the findings from that literature that are most relevant to our pur- poses, and provide some additional empirical results of our own. In particular,
1. The mechanisms underlying those effects are described in detail in Aiyagari, Christiano, and Eichenbaum (1990), Baxter and King (1993), Christiano and Eichenbaum (1992), and Fatás and Mihov (2001), among others. In a nutshell, an increase in (non-productive) government purchases, financed by current or future lump-sum taxes, has a negative wealth effect which is reflected in lower consumption. It also induces a rise in the quantity of labor supplied at any given wage. The latter effect leads, in equilibrium, to a lower real wage, higher employment and higher output. The increase in employment leads, if sufficiently persistent, to a rise in the expected return to capital, and may trigger a rise in investment. In the latter case the size of the multiplier is greater or less than one, depending on parameter values. 2. See, for example, Blanchard (2003). The total effect on output will also depend on the investment response. Under the assumption of a constant money supply, generally maintained in textbook versions of that model, the rise in consumption is accompanied by an investment decline (resulting from a higher interest rate). If instead the central bank holds the interest rate steady in the face of the increase in government spending, the implied effect on investment is nil. However, any “intermediate” response of the central bank (i.e., one that does not imply full accommodation of the higher money demand induced by the rise in output) will also induce a fall in investment in the IS-LM model.
“zwu001070405” — 2007/1/24 — page 228 — #2 Galí et al. Effects of Government Spending on Consumption 229 and like several other authors that preceded us, we find that a positive government spending shock leads to a significant increase in consumption, while investment either falls or does not respond significantly. Thus, our evidence seems to be con- sistent with the predictions of models with non-Ricardian consumers and hard to reconcile with those of the neoclassical paradigm. After reviewing the evidence, we turn to our paper’s main contribution: The development of a simple dynamic general equilibrium model that can potentially account for that evidence. Our framework shares many ingredients with recent dynamic optimizing sticky price models, though we modify the latter by allow- ing for the presence of rule-of-thumb behavior by some households.3 Following Campbell and Mankiw (1989), we assume that rule-of-thumb consumers do not borrow or save; instead, they are assumed to consume their current income fully. In our model, rule-of-thumb consumers coexist with conventional infinite-horizon Ricardian consumers. The introduction of rule-of-thumb consumers in our model is motivated by an extensive empirical literature pointing to substantial deviations from the perma- nent income hypothesis. Much of that literature provides evidence of “excessive” dependence of consumption on current income. That evidence is based on the analysis of aggregate time series,4 as well as natural experiments using micro data (e.g., response to anticipated tax refunds).5 That evidence also seems consis- tent with the observation that a significant fraction of households have near-zero net worth.6 On the basis of that evidence, Mankiw (2000) calls for the systematic incorporation of non-Ricardian households in macroeconomic models, and for an examination of the policy implications of their presence. As further explained below, the existence of non-Ricardian households cannot in itself generate a positive response of consumption to a rise in government spending. To see this, consider the following equilibrium condition
mpnt = µt + ct + ϕnt , where mpnt , ct , and nt represent the (logs) of the marginal product of labor, con- sumption, and hours worked, respectively. The term ct + ϕnt represents the (log) marginal rate of substitution, with parameter ϕ>0 measuring the curvature of the marginal disutility of labor. Variable µt is thus the wedge between the marginal rate of substitution and the marginal product of labor, and can be interpreted as the sum of both the (log) wage and price markups, as discussed in Galí, Gertler, and López-Salido (2007).
3. See, for example, Rotemberg and Woodford (1999), Clarida, Galí, and Gertler (1999), or Woodford (2003) for a description of the standard new Keynesian model. 4. See, for example, Campbell and Mankiw (1989) and Deaton (1992) and references therein. 5. See, for example, Souleles (1999) and Johnson, Parker, and Souleles (2004). 6. See, for example, Wolff (1998).
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Consider first an economy with a constant wedge, µt = µ for all t. Notice that the particular case of µ = 0 corresponds to the perfectly competitive case often assumed in the RBC literature. According to both theory and evidence, an increase in government purchases raises hours and, under standard assumptions, lowers the marginal product of labor. Thus, it follows that consumption must drop if the previous condition is to be satisfied. Hence, a necessary condition for consumption to rise in response to a fiscal expansion is the existence of a simulta- neous decline in the wedge µt . This motivates the introduction in our framework of the assumption of sticky prices in goods markets and, at least in one version of our model, of imperfectly competitive labor markets. Those complementary assumptions interact with the presence of non-Ricardian consumers in a way that makes it possible to reverse the sign of the response of consumption to changes in government spending. As described subsequently, our model predicts responses of aggregate consumption and other variables that are in line with the existing evidence, given plausible calibrations of the fraction of rule-of-thumb consumers, the degree of price stickiness, and the extent of deficit financing. Beyond the narrower focus of the present paper, a simple lesson emerges from our analysis: Allowing for deviations from the strict Ricardian behavior assumed in the majority of existing macro models may be required in order to capture important aspects of the economy’s workings.7 Our proposed framework, based on the simple model of rule-of-thumb consumers of Campbell and Mankiw (1989), although admittedly ad-hoc, provides in our view a good starting point. The rest of the paper is organized as follows. Section 2 describes the existing empirical literature and provides some new evidence. Section 3 lays out the model and its different blocks. Section 4 contains an analysis of the model’s equilibrium dynamics. Section 5 examines the equilibrium response to a government spending shock under alternative calibrations, focusing on the response of consumption and its consistency with the existing evidence. Section 6 summarizes the main findings of the paper and points to potential extensions and directions for further research.
2. An Overview of the Evidence
In the present section we start by summarizing the existing evidence on the response of consumption (and some other variables) to an exogenous increase in government spending, and providing some new evidence of our own. Most of the existing evidence relies on structural vector autoregressive models, with different papers using alternative identification schemes. Unfortunately, the data does not seem to speak with a single voice on this issue: Although some papers
7. In a companion paper (Galí, López-Salido, and Vallés 2004), we study the implications of rule-of-thumb consumers for the stability properties of Taylor-type rules.
“zwu001070405” — 2007/1/24 — page 230 — #4 Galí et al. Effects of Government Spending on Consumption 231 uncover a large, positive, and significant response of consumption, others find that such a response is small and often insignificant. As far as we know, however, there is no evidence in the literature pointing to the large and significant nega- tive consumption response that would be consistent with the predictions of the neoclassical model. Blanchard and Perotti (2002) and Fatás and Mihov (2001) identify exogenous shocks to government spending by assuming that the latter variable is predeter- mined relative to the other variables included in the VAR. Their most relevant findings for our purposes can be summarized as follows. First, a positive shock to government spending leads to a persistent rise in that variable. Second, the implied fiscal expansion generates a positive response in output, with the asso- ciated multiplier being greater than one in Fatás and Mihov, but close to one in Blanchard and Perotti. Third, in both papers the fiscal expansion leads to large (and significant) increases in consumption. Fourth, the response of investment to the spending shock is found to be insignificant in Fatás and Mihov, but negative (and significant) in Blanchard and Perotti. Here we provide some complementary evidence using an identification strat- egy similar to the above mentioned papers. Using U.S. quarterly data, we estimate the responses of several macroeconomic variables to a government spending shock. The latter is identified by assuming that government purchases are not affected contemporaneously (i.e., within the quarter) by the innovations in the other variables contained in a vector autoregression (VAR).8 Our VAR includes a measure of government spending, GDP, hours worked, consumption of non- durables and services, private nonresidential investment, the real wage, the budget deficit, and personal disposable income. In a way consistent with the model devel- oped herein, both government spending and the budget deficit enter the VAR as a ratio to trend GDP, where the latter is proxied by (lagged) potential output. The remaining variables are specified in logs, following convention.9
8. Qualitatively, the results herein are robust to the use of military spending (instead of total government purchases) as a predetermined variable in the VAR, as in Rotemberg and Woodford (1992). 9. We use quarterly U.S. data over the period 1954:I–2003:IV. The series were drawn from Estima’s USECON database (acronyms reported in brackets below). These include government (Federal + State + Local) consumption and gross investment expenditures (GH), gross domestic product (GDPH), a measure of aggregate hours obtained by multiplying total civilian employment (LE) by weekly average hours in manufacturing (LRMANUA), nonfarm business hours (LXNFH), the real compensation per hour in the nonfarm business sector (LXNFR), consumption of nondurable and services (CNH + CSH), non-residential investment (FNH), and the CBO estimate of potential GDP (GDPPOTHQ). All quantity variables are in log levels, and normalized by the size of the civil- ian population over 16 years old (LNN). We included four lags of each variable in the VAR. Our deficit measure corresponds to gross government investment (GFDI + GFNI + GSI) minus gross government savings (obtained from the FRED-II database). The resulting variable, expressed in nominal terms, was normalized by the lagged trend nominal GDP (GDPPOTQ). Finally, disposable income corresponds to real personal disposable income, also drawn from the FRED-II.
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Figure 1. The dynamic effects of a government spending shock. Note: Estimated impulse responses to a government spending shock in the large VAR. Sample Period 1954:I–2003:IV. The horizontal axis represents quarters after the shock. Confidence intervals correspond ±1 standard deviations of empir- ical distributions, based on 1,000 Monte Carlo replications. The right bottom panel plots the point estimates of both consumption (solid line) and disposable income (dashed line).
Figure 1 displays the estimated impulse responses. Total government spend- ing rises significantly and persistently, with a half-life of about four years. Output rises persistently in response to that shock, as predicted by the theory. Most inter- estingly, however, consumption is also shown to rise on impact and to remain persistently above zero. A similar pattern is displayed by disposable income; in fact, as shown in the bottom right graph, the response of consumption tracks, almost one-for-one, that of disposable income. With respect to the labor variables, our point estimates imply that both hours and the real wage rise persistently in response to the fiscal shock, although with some delay relative to government spending itself.10 By contrast, investment falls slightly in the short run, though the response is not significant. Finally, the deficit rises significantly on impact, remaining positive for about two years. Our point estimates in Figure 1 imply a government spending multiplier on output, dYt+k/dGt ,of0.78 on impact (k = 0), and of 1.74 at the end of the second year (k = 8). Such estimated multipliers are of a magnitude similar to the ones reported by Blanchard and Perotti (2002). They are also roughly consistent with the range of estimated short-run expenditure multipliers generated by a variety of
10. Fatás and Mihov (2001) also uncover a significant rise in the real wage in response to a spending shock, using compensation per hour in the non-farm business sector as a measure of the real wage. The positive comovement between hours and the real wage in response to a shock in military spending was originally emphasized by Rotemberg and Woodford (1992). See also Rotemberg and Woodford (1995).
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Table 1. Estimated effects of government spending shocks.
Estimated Fiscal Multipliers Implied Output Consumption Fiscal Parameters
1stQ 4thQ 8thQ 1stQ 4thQ 8thQ ρg φg φb 1948:I–2003:IV Baseline spending Small VAR 0.51 0.31 0.28 0.04 0.09 0.19 0.85 0.10 0.10 Larger VAR 0.41 0.31 0.68 0.07 0.11 0.49 0.80 0.06 0.06 Excluding military Small VAR 0.15 -0.12 0.34 -0.11 0.24 0.32 0.95 0.005 0.60 Larger VAR 0.36 0.62 1.53 0.03 0.51 0.68 0.94 0.005 0.60
1954:I–2003:IV Baseline spending Small VAR 0.74 0.75 1.22 0.14 0.46 0.73 0.95 0.13 0.20 Larger VAR 0.68 0.70 1.74 0.17 0.29 0.95 0.95 0.10 0.30 Excluding military Small VAR 0.63 1.95 2.60 0.25 1.41 1.12 0.95 0.05 0.50 Larger VAR 0.74 2.37 3.50 0.37 1.39 1.76 0.95 0.01 0.50
1960:I–2003:IV Baseline spending Small VAR 0.91 1.05 1.32 0.19 0.59 0.84 0.95 0.13 0.20 Larger VAR 0.81 0.44 0.76 0.20 0.25 0.45 0.95 0.08 0.20 Excluding military Small VAR 0.72 1.14 1.19 0.17 0.78 0.68 0.94 0.03 0.50 Larger VAR 1.13 1.89 2.08 0.40 1.14 1.07 0.98 0.01 0.55 Note: Large VAR corresponds to the 8-variable VAR described in the text; Small VAR estimates are based on a 4-variable VAR including government spending, output, consumption, and the deficit. Government spending excluding military was obtained as GFNEH + GSEH + GFNIH + GSIH. For each specification ρg is the AR(1) coefficient that matches the half-life of the estimated government spending response. Parameter φg is obtained as the difference of the VAR-estimated impact effects of government spending and deficit, respectively. Finally, given ρg and φg , we calibrate the parameter φb such that the dynamics of government spending (21) and debt (37) are consistent with the horizon at which the deficit is back to steady state, matching our empirical VAR responses of the fiscal deficit. macroeconometric models.11 Most important for our purposes is the observation that the multiplier on consumption is always positive, going from 0.17 on impact to 0.95 at the end of the second year. Table 1 illustrates the robustness of these findings to alternative specifications of the VAR, including number of variables (4 vs. 8 variables), sample period (full postwar, post–Korean war, and post-1960), and definition of government spending (excluding and including military spending).12 The left panel of the table reports the size of the multipliers on output and consumption at different horizons (on impact, one-year, and two-year horizons, respectively).13 Although the exact
11. See Hemming, Kell, and Mahfouz (2002) and the survey of the evidence provided in IMF (2004, Chap. 2). 12. See Table 1 for details. 13. The right panel is used herein for the purposes of model calibration.
“zwu001070405” — 2007/1/24 — page 233 — #7 234 Journal of the European Economic Association size of the estimated multipliers varies somewhat across specifications, the central finding of a positive response of consumption holds for the vast majority of cases.14 As previously mentioned, some papers in the literature call into question (or at least qualify) the previous evidence. Perotti (2004) applies the methodology of Blanchard and Perotti (2002) to several OECD countries. He emphasizes the evidence of subsample instability in the effects of government spending shocks, with the responses in the 1980s and 1990s being more muted than in the earlier period. Nevertheless, the sign and magnitude of the response of private con- sumption in Perotti’s estimates largely mimics that of GDP, both across countries and across sample periods. Hence, his findings support a positive comovement between consumption and income, conditional on government spending shocks, in a way consistent with the model developed herein (though at odds with the neoclassical model).15 Mountford and Uhlig (2004) apply the agnostic identification procedure orig- inally proposed in Uhlig (2005) to identify and estimate the effects of a “balanced budget” and a “deficit spending” shock.16 They find that government spending shocks crowd out both residential and non-residential investment, but they hardly change consumption (the response of the latter is small and insignificant). Ramey and Shapiro (1998) use a narrative approach to identify shocks that raise military spending, and which they codify by means of a dummy variable (widely known as the “Ramey-Shapiro dummy”). They find that nondurable con- sumption displays a slight, though hardly significant decline, whereas durables consumption falls persistently, but only after a brief but quantitatively large rise on impact. They also find that the product wage decreases, even though the real wage remains pretty much unchanged.17 Several other papers have used subsequently the identification scheme pro- posed by Ramey and Shapiro in order to study the effects of exogenous changes in government spending on different variables. Thus, Edelberg, Eichenbaum, and Fisher (1999) show that a Ramey-Shapiro episode triggers a fall in real wages, an increase in non-residential investment, and a mild and delayed fall in the con- sumption of nondurables and services, though durables consumption increases on impact. More recent work by Burnside, Eichenbaum, and Fisher (2003) using
14. The only exception corresponds to the small VAR specification over the full sample period and excluding military spending. Yet the underlying impulse responses (not shown) indicate that the slightly negative impact effect on consumption is quickly reversed in that case. 15. The response of private investment to the same shock tends to be negative, especially in the second sample period. 16. This method is based on sign and near-zero restrictions on impulse responses. 17. Ramey and Shapiro (1998) provide a potential explanation of the comovements of consumption and real wages in response to a change in military spending, based on a two-sector model with costly capital reallocation across sectors, and in which military expenditures are concentrated in one of the two sectors (manufacturing).
“zwu001070405” — 2007/1/24 — page 234 — #8 Galí et al. Effects of Government Spending on Consumption 235 a similar approach reports a flat response of aggregate consumption in the short run, followed by a small (and insignificant) rise in that variable several quarters after the Ramey-Shapiro episode is triggered. Another branch of the literature, exemplified by the work of Giavazzi and Pagano (1990), has uncovered the presence of “non-Keynesian effects” (i.e., neg- ative spending multipliers) during large fiscal consolidations, with output rising significantly despite large cuts in government spending. In particular, Perotti (1999) finds evidence of a negative comovement of consumption and govern- ment spending during such episodes of fiscal consolidation (and hence large spending cuts), but only in circumstances of “fiscal stress” (defined by unusually high debt/GDP ratios). In “normal” times, however, the estimated effects have the opposite sign, that is, they imply a positive response of consumption to a rise in government purchases. Nevertheless, as shown in Alesina and Ardagna (1998), the evidence of non-Keynesian effects during fiscal consolidations can hardly be interpreted as favorable to the neoclassical model because, on average, cuts in government spending raise both output and consumption during those episodes.18 Overall, we view the evidence discussed as tending to favor the predictions of the traditional Keynesian model over those of the neoclassical model. In particular, none of the evidence appears to support the kind of strong negative comovement between output and consumption predicted by the neoclassical model in response to changes in government spending. Furthermore, in trying to understand some of the empirical discrepancies discussed above it is worth emphasizing that the bulk of the papers focusing on the response to changes in government spending in “ordinary” times tend to support the traditional Keynesian hypothesis, in contrast with those that focus on “extraordinary” fiscal episodes (associated with wars or with large fiscal consolidations triggered by explosive debt dynamics). In light of those considerations, we view the model developed herein as an attempt to account for the effects of government spending shocks in “normal” times, as opposed to extraordinary episodes. Accordingly, we explore the condi- tions under which a dynamic general equilibrium model with nominal rigidities and rule-of-thumb consumers can account for the positive comovement of con- sumption and government purchases that arises in response to small exogenous variations in the latter variable.
3. A New Keynesian Model with Rule-of-Thumb Consumers
The economy consists of two types of households, a continuum of firms producing differentiated intermediate goods, a perfectly competitive firm producing a final good, a central bank in charge of monetary policy, and a fiscal authority. Next
18. See Table 6 in Alesina and Ardagna (1998).
“zwu001070405” — 2007/1/24 — page 235 — #9 236 Journal of the European Economic Association we describe the objectives and constraints of the different agents. Except for the presence of rule-of-thumb consumers, our framework consists of a standard dynamic stochastic general equilibrium model with staggered price setting à la Calvo.19
3.1. Households
We assume a continuum of infinitely lived households, indexed by i ∈[0, 1]. A fraction 1 − λ of households have access to capital markets where they can trade a full set of contingent securities, and buy and sell physical capital (which they accumulate and rent out to firms). We use the term optimizing or Ricardian to refer to that subset of households. The remaining fraction λ of households do not own any assets nor have any liabilities, and just consume their current labor income. We refer to them as rule-of-thumb households. Different inter- pretations for that behavior include myopia, lack of access to capital markets, fear of saving, ignorance of intertemporal trading opportunities, and so forth. Our assumptions imply an admittedly extreme form of non-Ricardian behavior among rule-of-thumb households, but one that captures in a simple and parsimonious way some of the existing evidence, without invoking a specific explanation. Campbell and Mankiw (1989) provide some aggregate evidence, based on estimates of a modified Euler equation, of the quantitative importance of such rule-of-thumb consumers in the U.S. and other industrialized economies.20
o o Optimizing households. Let Ct , and Lt represent consumption and leisure for optimizing households. Preferences are defined by the discount factor β ∈ (0, 1) o o and the period utility U(Ct ,Lt ). A typical household of this type seeks to maximize ∞ t o o E0 β U(Ct ,Nt ), (1) t=0 subject to the sequence of budget constraints
o + o + −1 o = o + k o + o + o − o Pt (Ct It ) Rt Bt+1 Wt Pt Nt Rt Pt Kt Bt Dt Pt Tt (2)
19. Most of the recent monetary models with nominal rigidities abstract from capital accumulation. A list of exceptions includes King and Watson (1996), Yun (1996), Dotsey (1999), Kim (2000) and Dupor (2002). In our framework, the existence of a mechanism to smooth consumption over time is important in order for the distinction between Ricardian and non-Ricardian consumers to be meaningful, thus justifying the need for introducing capital accumulation explicitly. 20. Mankiw (2000) reviews more recent microeconomic evidence consistent with that view.
“zwu001070405” — 2007/1/24 — page 236 — #10 Galí et al. Effects of Government Spending on Consumption 237 and the capital accumulation equation o o = − o + It o Kt+1 (1 δ)Kt φ o Kt . (3) Kt
o At the beginning of the period the consumer receives labor income Wt Pt Nt , o where Wt is the real wage, Pt is the price level, and Nt denotes hours of work. o He also receives income from renting his capital holdings Kt to firms at the (real) k o rental cost Rt . Bt is the quantity of nominally riskless one-period bonds carried over from period t −1, and paying one unit of the numéraire in period t. Rt denotes o the gross nominal return on bonds purchased in period t. Dt are dividends from o ownership of firms, Tt denotes lump-sum taxes (or transfers, if negative) paid by o o these consumers. Ct and It denote, respectively, consumption and investment expenditures, in real terms. Pt is the price of the final good. Capital adjustment o o o costs are introduced through the term φ(It /Kt )Kt , which determines the change o in the capital stock induced by investment spending It . We assume φ > 0, and φ ≤ 0, with φ(δ) = 1, and φ(δ) = δ. In what follows we specialize the period utility—common to all households—to take the form
N 1+ϕ U(C,L) ≡ log C − , 1 + ϕ where ϕ ≥ 0. The first order conditions for the optimizing consumer’s problem can be written as Pt 1 = Rt Et t,t+1 , (4) P + t 1 I o = k + − + − t+1 Qt Et t,t+1 Rt+1 Qt+1 (1 δ) φt+1 o φt+1 , (5) Kt+1 = 1 Qt o , (6) It φ o Kt where t,t+k is the stochastic discount factor for real k-period ahead payoffs given by